A processing method for correcting the wall thickness difference of a cast pipe mold

Abstract

The present application relates to a kind of processing methods for correcting the wall thickness difference of casting pipe mold, the wall thickness difference of which is φ180mm-φ300mm, the processing method is as follows: when processing the inner hole of casting pipe mold, the core bending caused by sleeve inner hole appears inner hole deflection, which often causes the wall thickness difference of the position about 1500-2000mm away from the mark end to be out of tolerance, if continue to sleeve hole, the inner hole will be more deflected, thus leading to the wall thickness difference of casting pipe mold to be out of tolerance and scrapped, the workpiece is corrected by oil pressure straightening machine, the thickest wall thickness of casting pipe mold is pressed and corrected as high point, after pressing and correcting, the frame position is turned on lathe, to ensure that the wall thickness difference of frame position is ≤1.5mm, then the outer circle is left with 7mm machining allowance, the outer circle is rough turned, the workpiece is aligned on deep hole drilling and boring machine with outer circle, φ(D-10)mm hole is drilled in sleeve, the inner hole is drilled through, the core falls off, after reversing, φDmm through hole is bored, the outer circle is turned on lathe, to ensure the wall thickness difference requirement of the whole length of casting pipe mold, to ensure the wall thickness difference requirement of casting pipe mold, and to save the processing quality of product.

Description

Technical Field

[0001] This invention belongs to the field of machining technology, specifically relating to a machining method for correcting excessive wall thickness differences in cast pipe molds with inner diameters of φ180mm to φ300mm. Background Technology

[0002] Processing such as Figure 1 The shown pipe mold has a length of 6-7m and an inner diameter of φ180mm-φ300mm. Deep holes in these molds are typically machined on a deep-hole drilling and boring machine. Drilling begins from the marked end, and a φD insert cutter is used to insert the φD through hole. During inserting, the insert core is bent, causing skew in the inner hole. This often results in excessive wall thickness variation (12mm-15mm) at a position approximately 1500-2000mm from the marked end. However, the product processing requirements stipulate a wall thickness variation of only 3mm along the entire length of the mold. Continuing to insert the insert further exacerbates the skew, resulting in a wall thickness variation far exceeding 15mm. Since the machining allowance for the outer diameter of the mold is typically 15mm, this leads to excessive wall thickness variation and the mold being scrapped. Therefore, we need to design a machining method to correct the excessive wall thickness variation in pipe molds with inner diameters of φ180mm-φ300mm. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a processing method for improving processing quality, reducing the wall thickness difference of the casting mold, and performing salvage processing to correct the excessive wall thickness difference of the casting mold.

[0004] The technical solution of this invention is implemented as follows: A processing method for correcting excessive wall thickness difference in cast pipe molds, specifically a processing method for correcting inner hole deviation in cast pipe molds with inner diameters of φ180mm to φ300mm, is as follows:

[0005] Step 1) Measure the wall thickness at the bottom of the blind hole of the cast pipe mold using a wall thickness gauge along the outer circumference of the bottom of the blind hole, and mark the thickest point and the difference in wall thickness.

[0006] Step 2) Place the pipe mold with the thickest point marked on it on the hydraulic straightening machine for pressure straightening. First, straighten the pipe mold to ensure that the straightness of the entire length of the pipe mold is ≤3mm. Then, apply force F to press the thickest point of the pipe mold wall as the high point. The runout of the high point is the wall thickness difference.

[0007] Step 3) Machining the pressed and aligned casting mold on a lathe. The lathe's four-jaw chuck clamps the outer circle of the marked end of the casting mold, and the tailstock center of the lathe abuts against the center hole of the non-marked end of the casting mold. The frame is positioned 1500-2000mm away from the marked end of the casting mold. By adjusting the four-jaw chuck, the wall thickness difference at the frame position is ensured to be ≤1.5mm. Then, the frame position is supported by the center rest, and the outer circle is rough machined with a 7mm machining allowance.

[0008] Step 4) After rough turning the outer diameter of the casting pipe mold, it is then machined on a deep hole drilling and boring machine. The outer diameter is aligned and the runout of the outer diameter along the entire length is ≤0.5mm. The chuck of the deep hole drilling and boring machine clamps the outer diameter and drills from the non-marked end to fit the φ(D-10)mm inner hole. That is, the diameter of the inner hole to be fitted is 10mm smaller than φD. After the inner hole of the casting pipe mold is fitted through, the core is removed.

[0009] Step 5) Turn the casting mold around on the deep hole drilling and boring machine, align the outer circle, and ensure that the runout of the outer circle along the entire length is ≤0.5mm. Clamp the outer circle with the chuck of the deep hole drilling and boring machine, and bore the through hole from the marked end using a φD nesting tool.

[0010] Step 6) Place the mold on a lathe and, using the inner hole for positioning, turn the outer diameter of the casting mold to the dimensions required by the drawing.

[0011] The positive effects of the technical solution of this invention are as follows: a processing method for correcting the inner hole deviation of a casting pipe mold with an inner diameter of φ180mm~φ300mm, solving the problem of excessive wall thickness difference in the inner hole of the casting pipe mold. Processing Figure 1 As shown in the diagram, when the inner hole of the pipe casting mold with a diameter of φD is fitted, the inner hole deviates due to the bending of the fitted core. An excessive wall thickness difference of 12mm to 15mm occurs at a position approximately 1500-2000mm from the marked end of the pipe casting mold. However, the product processing technology requires the wall thickness difference of the entire length of the pipe casting mold to be only 3mm. If the fitting continues, the inner hole will deviate further, resulting in a wall thickness difference far exceeding 15mm. The machining allowance for the outer diameter of the pipe casting mold is usually 15mm, thus causing the pipe casting mold to be scrapped due to the excessive wall thickness difference.

[0012] This invention salvages casting molds that are scrapped due to inner hole misalignment caused by core bending during the molding process, preventing further molding from resulting in excessive wall thickness variation. It effectively reduces inner hole misalignment and workpiece wall thickness variation, controlling the wall thickness variation of the finished casting mold to within 3mm, thus improving product quality. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a pipe casting mold.

[0014] Figure 2 This is a schematic diagram of the straightening process of the present invention.

[0015] Figure 3 This is a schematic diagram of the vehicle frame position according to the present invention.

[0016] Figure 4 This is a schematic diagram of the sleeve hole of the present invention.

[0017] As shown in the diagram: 1. Core material Detailed Implementation

[0018] A machining method for correcting excessive wall thickness differences in pipe casting molds, specifically for correcting inner hole deviations in pipe casting molds with inner diameters ranging from φ180mm to φ300mm, is as follows:

[0019] Step 1) Measure the wall thickness at the bottom of the blind hole of the cast pipe mold using a wall thickness gauge along the outer circumference of the bottom of the blind hole, and mark the thickest point and the difference in wall thickness.

[0020] Step 2) Place the cast pipe mold with the thickest point marked on it on the hydraulic straightening machine for pressure straightening, such as... Figure 2 First, straighten the pipe mold to ensure that the straightness of the entire length of the pipe mold is ≤3mm. Then, apply force F to press the thickest point of the pipe mold wall as the high point. The runout of the high point is the wall thickness difference.

[0021] Step 3) The pressed and aligned casting mold is machined on a lathe. The lathe's four-jaw chuck clamps the outer diameter of the marked end of the casting mold, and the tailstock center of the lathe abuts against the center hole of the non-marked end of the casting mold. Figure 3 At the position shown (approximately 1500-2000mm from the end of the casting mold mark), the frame position is adjusted to ensure that the wall thickness difference at the frame position is ≤1.5mm by adjusting the four-jaw chuck. Then, the frame position is supported by the center support, and the outer circle is rough machined after leaving a 7mm machining allowance.

[0022] Step 4) After rough turning the outer diameter of the cast pipe mold, it is then machined on a deep hole drilling and boring machine, according to... Figure 4 As shown, align the outer circle, with the total runout of the outer circle ≤ 0.5mm. Clamp the outer circle with the chuck of the deep hole drilling and boring machine, and drill from the non-marked end. Fit the φ(D-10)mm inner hole, that is, the diameter of the inner hole to be fitted is 10mm smaller than φD. After the inner hole of the casting pipe mold is fitted through, take out the core material.

[0023] Step 5) Turn the casting mold around on the deep hole drilling and boring machine, align the outer circle, and ensure that the runout of the outer circle along the entire length is ≤0.5mm. Clamp the outer circle with the chuck of the deep hole drilling and boring machine, and bore the through hole from the marked end using a φD nesting tool.

[0024] Step 6) Place the mold on a lathe and, using the inner hole for positioning, turn the outer diameter of the casting mold to the dimensions required by the drawing.

[0025] Example 1: Casting mold: Material: 21CrMo10; Specifications: Inner hole of the casting mold is Φ190mm, length: 6300mm. When the inner hole of the casting mold is Φ190mm, the core is bent, causing the inner hole to be skewed. This results in a wall thickness difference of 13mm at 1820mm from the marked end. Moreover, the thickest part of the wall is at the lowest point of the bend. If the inner hole is further machined, the hole will become increasingly skewed, leading to a larger and larger wall thickness difference in the casting mold, eventually rendering it unusable.

[0026] The specific processing steps are as follows:

[0027] Step 1) Measure the wall thickness of the bottom of the blind hole of the cast pipe mold (1820mm from the marked end) using a wall thickness gauge along the outer circumference of the bottom of the blind hole of the cast pipe mold. Mark the thickest point and the wall thickness difference of 13mm.

[0028] Step 2) Place the pipe mold with the thickest point marked on it on the hydraulic straightening machine for pressure straightening. First, straighten the pipe mold to ensure that the straightness of the entire length of the pipe mold is ≤3mm. Then, press the thickest point of the pipe mold wall as the high point, and the runout of the high point is 13mm.

[0029] Step 3) Machining the pressed and aligned casting mold on a lathe. The lathe's four-jaw chuck clamps the outer circle of the marked end of the casting mold, and the tailstock center of the lathe abuts against the center hole of the non-marked end of the casting mold. The frame position is set at a distance of 1820mm from the marked end of the casting mold. By adjusting the four-jaw chuck, it is ensured that the wall thickness difference at the frame position is ≤1.5mm. Then, the frame position is supported by the center rest, and the outer circle is rough machined with a machining allowance of 7mm.

[0030] Step 4) After rough turning the outer diameter, the casting mold is then machined on a deep hole drilling and boring machine. The outer diameter is aligned, and the total runout of the outer diameter is ≤0.5mm. The chuck of the deep hole drilling and boring machine clamps the outer diameter, and the drill enters from the non-marked end to fit the φ180mm inner hole. After the inner hole is slit through, the core is removed.

[0031] Step 5) Turn the casting mold around on the deep hole drilling and boring machine, align the outer circle, and ensure that the runout of the outer circle along the entire length is ≤0.5mm. Clamp the outer circle with the chuck of the deep hole drilling and boring machine, and bore the through hole from the marked end using a φ190mm nesting tool.

[0032] Step 6) On the lathe, using the inner hole for positioning, turn the outer circle of the casting mold to the dimensions required by the drawing. After machining, the wall thickness difference at three points along the entire length of the casting mold is 1.4mm, 1.6mm, and 1.3mm, which meets the requirement that the wall thickness difference of the casting mold be controlled within 3mm, thus achieving the effect of salvaging product quality.

Claims

1. A machining method for correcting excessive wall thickness difference in cast pipe molds, characterized in that: the machining method for correcting the inner hole deviation of cast pipe molds with an inner diameter of φ180mm~φ300mm is as follows: Step 1) Measure the wall thickness at the bottom of the blind hole of the cast pipe mold using a wall thickness gauge along the outer circumference of the bottom of the blind hole, and mark the thickest point and the difference in wall thickness. Step 2) Place the pipe mold with the thickest point marked on it on the hydraulic straightening machine for pressure straightening. First, straighten the pipe mold to ensure that the straightness of the entire length of the pipe mold is ≤3mm. Then, apply force F to press the thickest point of the pipe mold wall as the high point. The runout of the high point is the wall thickness difference. Step 3) Machining the pressed and aligned casting mold on a lathe. The lathe's four-jaw chuck clamps the outer circle of the marked end of the casting mold, and the tailstock center of the lathe abuts against the center hole of the non-marked end of the casting mold. The frame is positioned 1500-2000mm away from the marked end of the casting mold. By adjusting the four-jaw chuck, the wall thickness difference at the frame position is ensured to be ≤1.5mm. Then, the frame position is supported by the center rest, and the outer circle is rough machined with a 7mm machining allowance. Step 4) After rough turning the outer diameter of the casting pipe mold, it is then machined on a deep hole drilling and boring machine. The outer diameter is aligned and the runout of the outer diameter along the entire length is ≤0.5mm. The chuck of the deep hole drilling and boring machine clamps the outer diameter and drills from the non-marked end to fit the φ(D-10)mm inner hole. That is, the diameter of the inner hole to be fitted is 10mm smaller than φD. After the inner hole of the casting pipe mold is fitted through, the core is removed. Step 5) Turn the casting mold around on the deep hole drilling and boring machine, align the outer circle, and ensure that the runout of the outer circle along the entire length is ≤0.5mm. Clamp the outer circle with the chuck of the deep hole drilling and boring machine, and bore the through hole from the marked end using a φD nesting tool. Step 6) Place the mold on a lathe and, using the inner hole for positioning, turn the outer diameter of the casting mold to the dimensions required by the drawing.

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